Hi. The first thing i would do is dig a hole and fill it with water to see if the problem is indeed poor drainage. It might also be a high amount of salt in the soil.The easiest to get rid of soil problem is to garden on raised bed:http://en.wikipedia.org/wiki/Raised-bed_gardening(note that all the picture show frame around the bed, but those are not absolutely needed).You can always use French drain around the garden but that will only be effective if you have a very sandy soil and on a sufficiently high area to deverse the surplus water into a lower area.